/* crypto/dh/dh.h */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#ifndef HEADER_DH_H
#define HEADER_DH_H

#include <openssl/e_os2.h>

#ifdef OPENSSL_NO_DH
#error DH is disabled.
#endif

#ifndef OPENSSL_NO_BIO
#include <openssl/bio.h>
#endif
#include <openssl/ossl_typ.h>
#ifndef OPENSSL_NO_DEPRECATED
#include <openssl/bn.h>
#endif

#ifndef OPENSSL_DH_MAX_MODULUS_BITS
# define OPENSSL_DH_MAX_MODULUS_BITS    10000
#endif

#define DH_FLAG_CACHE_MONT_P     0x01
#define DH_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DH
                                       * implementation now uses constant time
                                       * modular exponentiation for secret exponents
                                       * by default. This flag causes the
                                       * faster variable sliding window method to
                                       * be used for all exponents.
                                       */

/* If this flag is set the DH method is FIPS compliant and can be used
 * in FIPS mode. This is set in the validated module method. If an
 * application sets this flag in its own methods it is its reposibility
 * to ensure the result is compliant.
 */

#define DH_FLAG_FIPS_METHOD            0x0400

/* If this flag is set the operations normally disabled in FIPS mode are
 * permitted it is then the applications responsibility to ensure that the
 * usage is compliant.
 */

#define DH_FLAG_NON_FIPS_ALLOW            0x0400

#ifdef  __cplusplus
extern "C" {
#endif

/* Already defined in ossl_typ.h */
/* typedef struct dh_st DH; */
/* typedef struct dh_method DH_METHOD; */

struct dh_method
    {
    const char *name;
    /* Methods here */
    int (*generate_key)(DH *dh);
    int (*compute_key)(unsigned char *key,const BIGNUM *pub_key,DH *dh);
    int (*bn_mod_exp)(const DH *dh, BIGNUM *r, const BIGNUM *a,
                const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx,
                BN_MONT_CTX *m_ctx); /* Can be null */

    int (*init)(DH *dh);
    int (*finish)(DH *dh);
    int flags;
    char *app_data;
    /* If this is non-NULL, it will be used to generate parameters */
    int (*generate_params)(DH *dh, int prime_len, int generator, BN_GENCB *cb);
    };

struct dh_st
    {
    /* This first argument is used to pick up errors when
     * a DH is passed instead of a EVP_PKEY */
    int pad;
    int version;
    BIGNUM *p;
    BIGNUM *g;
    long length; /* optional */
    BIGNUM *pub_key;    /* g^x */
    BIGNUM *priv_key;    /* x */

    int flags;
    BN_MONT_CTX *method_mont_p;
    /* Place holders if we want to do X9.42 DH */
    BIGNUM *q;
    BIGNUM *j;
    unsigned char *seed;
    int seedlen;
    BIGNUM *counter;

    int references;
    CRYPTO_EX_DATA ex_data;
    const DH_METHOD *meth;
    ENGINE *engine;
    };

#define DH_GENERATOR_2        2
/* #define DH_GENERATOR_3    3 */
#define DH_GENERATOR_5        5

/* DH_check error codes */
#define DH_CHECK_P_NOT_PRIME        0x01
#define DH_CHECK_P_NOT_SAFE_PRIME    0x02
#define DH_UNABLE_TO_CHECK_GENERATOR    0x04
#define DH_NOT_SUITABLE_GENERATOR    0x08

/* DH_check_pub_key error codes */
#define DH_CHECK_PUBKEY_TOO_SMALL    0x01
#define DH_CHECK_PUBKEY_TOO_LARGE    0x02

/* primes p where (p-1)/2 is prime too are called "safe"; we define
   this for backward compatibility: */
#define DH_CHECK_P_NOT_STRONG_PRIME    DH_CHECK_P_NOT_SAFE_PRIME

#define d2i_DHparams_fp(fp,x) (DH *)ASN1_d2i_fp((char *(*)())DH_new, \
        (char *(*)())d2i_DHparams,(fp),(unsigned char **)(x))
#define i2d_DHparams_fp(fp,x) ASN1_i2d_fp(i2d_DHparams,(fp), \
        (unsigned char *)(x))
#define d2i_DHparams_bio(bp,x) ASN1_d2i_bio_of(DH,DH_new,d2i_DHparams,bp,x)
#define i2d_DHparams_bio(bp,x) ASN1_i2d_bio_of_const(DH,i2d_DHparams,bp,x)

DH *DHparams_dup(DH *);

const DH_METHOD *DH_OpenSSL(void);

void DH_set_default_method(const DH_METHOD *meth);
const DH_METHOD *DH_get_default_method(void);
int DH_set_method(DH *dh, const DH_METHOD *meth);
DH *DH_new_method(ENGINE *engine);

DH *    DH_new(void);
void    DH_free(DH *dh);
int    DH_up_ref(DH *dh);
int    DH_size(const DH *dh);
int DH_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
         CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func);
int DH_set_ex_data(DH *d, int idx, void *arg);
void *DH_get_ex_data(DH *d, int idx);

/* Deprecated version */
#ifndef OPENSSL_NO_DEPRECATED
DH *    DH_generate_parameters(int prime_len,int generator,
        void (*callback)(int,int,void *),void *cb_arg);
#endif /* !defined(OPENSSL_NO_DEPRECATED) */

/* New version */
int    DH_generate_parameters_ex(DH *dh, int prime_len,int generator, BN_GENCB *cb);

int    DH_check(const DH *dh,int *codes);
int    DH_check_pub_key(const DH *dh,const BIGNUM *pub_key, int *codes);
int    DH_generate_key(DH *dh);
int    DH_compute_key(unsigned char *key,const BIGNUM *pub_key,DH *dh);
DH *    d2i_DHparams(DH **a,const unsigned char **pp, long length);
int    i2d_DHparams(const DH *a,unsigned char **pp);
#ifndef OPENSSL_NO_FP_API
int    DHparams_print_fp(FILE *fp, const DH *x);
#endif
#ifndef OPENSSL_NO_BIO
int    DHparams_print(BIO *bp, const DH *x);
#else
int    DHparams_print(char *bp, const DH *x);
#endif

#define EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, len) \
    EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DH, EVP_PKEY_OP_PARAMGEN, \
            EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN, len, NULL)

#define EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, gen) \
    EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DH, EVP_PKEY_OP_PARAMGEN, \
            EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR, gen, NULL)

#define    EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN    (EVP_PKEY_ALG_CTRL + 1)
#define    EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR    (EVP_PKEY_ALG_CTRL + 2)


/* BEGIN ERROR CODES */
/* The following lines are auto generated by the script mkerr.pl. Any changes
 * made after this point may be overwritten when the script is next run.
 */
void ERR_load_DH_strings(void);

/* Error codes for the DH functions. */

/* Function codes. */
#define DH_F_COMPUTE_KEY                 102
#define DH_F_DHPARAMS_PRINT_FP                 101
#define DH_F_DH_BUILTIN_GENPARAMS             106
#define DH_F_DH_COMPUTE_KEY                 114
#define DH_F_DH_GENERATE_KEY                 115
#define DH_F_DH_GENERATE_PARAMETERS_EX             116
#define DH_F_DH_NEW_METHOD                 105
#define DH_F_DH_PARAM_DECODE                 107
#define DH_F_DH_PRIV_DECODE                 110
#define DH_F_DH_PRIV_ENCODE                 111
#define DH_F_DH_PUB_DECODE                 108
#define DH_F_DH_PUB_ENCODE                 109
#define DH_F_DO_DH_PRINT                 100
#define DH_F_GENERATE_KEY                 103
#define DH_F_GENERATE_PARAMETERS             104
#define DH_F_PKEY_DH_DERIVE                 112
#define DH_F_PKEY_DH_KEYGEN                 113

/* Reason codes. */
#define DH_R_BAD_GENERATOR                 101
#define DH_R_BN_DECODE_ERROR                 109
#define DH_R_BN_ERROR                     106
#define DH_R_DECODE_ERROR                 104
#define DH_R_INVALID_PUBKEY                 102
#define DH_R_KEYS_NOT_SET                 108
#define DH_R_KEY_SIZE_TOO_SMALL                 110
#define DH_R_MODULUS_TOO_LARGE                 103
#define DH_R_NON_FIPS_METHOD                 111
#define DH_R_NO_PARAMETERS_SET                 107
#define DH_R_NO_PRIVATE_VALUE                 100
#define DH_R_PARAMETER_ENCODING_ERROR             105

#ifdef  __cplusplus
}
#endif
#endif
